trying to save skoonsus LCD tv.
looks like power supply board busted. Samsung don't sell the board. They want you to bring it in for them to repair and will charge you arm and leg no doubt.
so i took out few components that looked dodge. got the diodes but cannot find capacitor.

68uf / 200V. Am i right to say you can actually go slightly higher for the voltage? what is the max? or should you stick to the same. Where could i find one of these? Mantech and communica don't stock it.

no.
was not to sure how to reliably test it with standard multimeter. conflicting reports say you need special capacitor meter to accurately test...
it was bulging at top, and had slight rust marks... at R10 each.. better just to replace it.

You could also replace all the other electrolytics as well, they're cheap enough. Use the correct resin-cored solder - usually wound on a red spool, and not acid-core - usually on a black spool. Ensure you get the polarity correct when replacing caps, otherwise the smoke escapes rather violently.

Testing for capacitance values is not good enough: One needs to measure the ESR (equivalent series resistance) because this can increase with age and cause problems.